Traditional ducts are made of galvanized steel or aluminum. These metal ducts are generally straight and rigid. Installing them requires a fair amount of planning and design. A flexible duct can connect metal ductwork to individual grills and registers. However, it is increasingly being used as an alternative to hard metal ductwork. Here are some pros and cons associated with this kind of installation.
What Is Flexible Ductwork?Like metal ducts, flexible tubing provides a path for air to flow. It branches from the main plenum to different rooms and to the main components of your heating and ventilation system. Flexible ducts are made of a round wire coil encased in bendable polymer skin. Fiberglass insulation often surrounds the plastic wall and a thin polyethylene or foil jacket covers the insulating layer. A flex duct may also be made of PVC, rubber, silicone, or stainless steel.
Pros of Flexible DuctsLess Costly to Install:
- Flexible ductwork is cheaper when you consider materials, installation, and labor costs. Less skill and effort are required to install it. On the other hand, metal ducts are almost twice as expensive and a fair amount of effort is needed to seal joints, seams, and elbows.
- Installing metal ducts requires precise measuring and fitting, along with computer design tools to plan the system. Flexible materials can be manipulated to fit around corners and through tight spaces, so are suited for just about any home.
- Flexible ducts require much less effort to install; therefore, installation projects can be completed much faster than rigid metal ducts.
- The vibrations, whistling, and other sounds transmitted through a heating & air conditioning system by metal ducts are eliminated when flexible ductwork is installed.
- Duct sections made of metal are often limited to just 3 feet long. This requires many seams throughout the system, which can leak as much as 30% of heated or cooled air, as estimated by the S. Department of Energy.
Cons of Flexible DuctsHigher Energy Costs:
- When flex ducts are bent and twisted around obstacles, it creates drag and reduces airflow, so more energy is required to circulate air.
- Compared to traditional metal ductwork, flexible tubing is more prone to tears, punctures, and other damage. It also becomes brittle over time.
- The tools used to clean traditional air ducts are too harsh for flexible tubes. They can easily damage the thin polymer lining. More sensitive cleaning tools and methods are needed to safely clean these duct systems.
- The softer nature of flexible ductwork makes it prone to issues like pinching, twisting, and compression. It’s also more susceptible to damage by rodents, insects, and other pests.
- Under ordinary conditions, metal ductwork will outlast flexible ducts unless it is installed in a highly corrosive environment. Most of the time, flex ducts won’t last more than 20 or 25 years.